<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
  <style>
    div{
      font-size: 100px;
      background: skyblue;
      height: 400px;
      
    }
    span{
    
      font-size: 40px;
      vertical-align: baseline;
      background-color: red;
      /* vertical-align:baseline */
    }
  </style>
</head>
<body>
<div>今天天气如何x<span>x晴朗</span></div>
</body>
</html>